Stable petroleum distillate fuels



United States Patent 3,084,034 STABLE PETROLEUM DISTILLATE FUELS Mathew L. Knlinowski, Chicago, lli., assignor to Standard Oil Company, Chicago, 111., a corporation of Indiana No Drawing. Filed Nov. 30, 1953, Ser. No. 395,272 Claims. (CI. 4466) This invention relates to stable petroleum distillates. It is particularly concerned with preventing deterioration of fuel oil compositions higher boiling than gasoline.

The deterioration due to oxidation and the like of distillate fuels, particularly in the diesel oil and furnace oil range, manifests itself, for example, through the appearance of color, sediment, etc. in the oil. Sediment formation is usually the most troublesome since sludging resulting therefrom causes clogging of fuel system equipment such as filters, screens, and nozzles.

It is an object of the present invention to provide an additive for petroleum distillate oils, which additive will inhibit sediment and color formation in the oils. It is another object to disperse and to thus render harmless deterioration products occurring in such oils before the addition of the additive. Still another object is to provide fuel oils resistant to sedimentation and sludging.

It is a further object of the present invention to provide sludge-preventing additives for fuel oils. These and additional objects will be apparent from the following detailed description of the present invention.

In accordance with the present invention, sediment formation may be prevented and oils of good color and overall stability may be assured by adding to petroleum distillate fuel oils, e.g. furnace oils or diesel fuel oils, a small amount of at least one polyamino compound of the hereinafter defined class. More specifically, it has been found that a high degree of stabilization of distillate oils may be obtained by adding thereto an amount of from about 0.001% to about 0.1%. and preferably from 0.005 to about 0.05%, e.g. about 0.01% of at least one N-alkyl substituted propylene diarnino compound selected from the group consisting of N-alkyl propylene diarnines containing one primary amino nitrogen atom and aliphatic carboxylic acid salts of such N-alkyl propylene diamines wherein there are from about 16 to about carbon atoms in the N-alkyl radical. Thus, for example, distillate oils containing no more than 0.005% of an additive comprising an N-alkyl propylene diamine and/or an oleic acid salt of such amine have shown striking stability as compared to the same oils without the additive.

More specifically, there may be employed such amines as N-n-cetyl-propylene diamine, Duorneen T and Duomeen S (products of Armour Chemical Division) which have the general formula RNHCH CH CH NH wherein R is derived from tallow fatty acid Duomeen T) and from soya fatty acid (Duomeen S) respectively, etc. The Duomeens" are industrial or technical grade chemicals with an amine content of approximately 80% calculated as di-amine. The approximate melting ranges for each of the aforementioned Duomeens are: Duomeen S -38 to 42 C., and Duomeen T 44" to 48 C.

The salts which may be employed in accordance herewith may be prepared by reacting, under carefully controlled, nondehydrating conditions, i.e. below about 200 F. and preferably below about 195 R, an aliphatic carboxylic acid containing from about 6 to about 20 carbon atoms, e.g. hexanoic, nonanoic, lauric, stearic,

3,084,034 Patented Apr. 2, 1963 "ice oleic, linoleic, linolenic, palmitic, etc., with any of the hereinabove described amines to obtain either the monoor di-substituted acid salts of the amines. Care must be taken in the preparation of such salts inasmuch as prolonged exposure to temperatures higher than about 200 F. results in the formation of amides or even glyoxalidines (if l,2-substituted polyamines are employed) upon splitting out water. Among the very economical, commercially available salts of this type are the oleic acid monoand/or di-salts of the Duomeens (above described), particularly of Duomeen T.

The oils which may be improved in their stability by the addition of the hereinabove described amines and amine salts are those distillates generally useful for heating purposes, either domestic or industrial. Thus, oils such as furnace oils, burner oils, kerosene, etc. which boil chiefly between about 375 F. and about 750 F., and preferably between about 400 and 650 F., and which are subject to sedimentation and discoloration in storage, are readily stabilized in accordance herewith. The deterioration of such oils to produce troublesome sludge and discoloration is a problem obviously quite different from that of gasoline wherein the use of gum inhibitors such as phenylene diamine have proven very satisfactory. The total ineffectiveness of this amine in furnace oils is shown in Table l.

The oils which may be stabilized by the additives of the present invention may be cracked, virgin or mixtures of these. Even blends of two different virgin oils, which because of solubility differences result in the formation of sediment when admixed, may be stabilized thereby. Because, however, the presence of cracked stocks in fuel oils appear to result in greater instability, the additives of the present invention have particular utility in such oils.

Whereas the additives of the present invention are generally useful in petroleum fuel oils, and particularly in those comprising cracked distillate oils, they are especially useful in stocks of the type generally referred to as light catalytic cycle oil and fuels containing such an oil. Such a catalytic cycle oil is obtained from a catalytic hydrocarbon cracking operation in which a gas oil or heavier hydrocarbons such as reduced crude is cracked at a temperature of about 800 F. to about 1050 F. at a pressure of about atmospheric to about 50 pounds per square inch in the presence of suitable catalysts, such as for example silica-magnesia, silica-alumina, and other well-known cracking catalysts. A method of conducting a fluidized catalytic cracking operation is described in U.S. 2,341,193 issued to Fred W. Scheineman, February 8, 1944. The product fraction referred to herein is. the heavier-than gasoline fraction ordinarily called light gas oil or catalytic light cycle stock. A catalytic light cycle stock of the type particularly suitable for blending with virgin heavy distil lates is a fraction having an aromatic content of at least about 40 to about 50% and adistillation range between about 425 F. and about 560 F. A typical analysis of a suitable light catalytic cycle stock shows the material to be composed substantially of about 10% normal C to C parafllns, about of other paraifins and naphthenes, about 5% mono-nuclear aromatics which are mainly monoto hexa-alkylated benzenes, and about 40% polynuclear aromatics which are mainly alkyl naphthalenes, largely methylated naphthalenes. The boiling range of a typical light catalytic cycle stock by A.S.T.M. distillation may be approximately:

F. Initial boiling point 430 F. over 448 50% over 478 90% over 518 Maximum boiling point 552 The boiling range of particular cycle oils may, of course, vary over a considerably wider range, depending upon catalyst cracking conditions, charge stock, etc. Thus, catalytic cycle oils, generally, may boil within the range from about 325 F. to about 700 F. or higher. Moreover, it should be understood that the additives of this invention will inhibit sludge, color, etc. in any oil comprising cracked oils (thermally or catalytic-ally) or in virgin distillates or mixtures thereof boiling chiefly within such range. The oils to which the additives of the present invention are added may have been refined by any of the many well-known techniques, e.g. caustic washing, acid treatment, doctor sweetening, clay treating, etc. prior to additive introduction.

Table 2 10 Example Additi e Amount Color Brightness Sediment 1 Duomccn T..- .005 Light. Bright Morlcrate. 2 Duomcrn'l .005 do... S1. Cloudy Do.

Mnno-olcate. 3 Duonieen '1 .005 do do Do. Di-olcntu.

4 Control Dark" V. Clondy Much.

The introduction of additives comprising two or more constituents of the type above described to fuels and the Table 1 DllOl'ilCOlt Example Amine Amount T hlono- Cl'LlClllli,4 )IlIlQi]lilllCC Color D Brightness l Sediment b Oleatc 1 (Control) Deep Purple l lcclrs. V. Cloudy Much. Duomoen T .(Jl link Mai... Clear. None.

Duomcen S. .002] Red brown Crista. do 110. .do .008 002 Light Pink Cast do Do.

Duomeen T 008 .002 Pink Cast... Cloudy. Slight. Ihcnylcnedizunnnn .01 Dense Brown Mat" V. Cloudy. Much. I do.. .008 .002 Deep Purple Man Cloudy. Moderate.

B 500 milliliter samples of furnace oil, with and without additive, were shaken with 500 ml. of tap water in u sepnrntory funnel The oil and water layers were allowed to separate [or minutes; the free water was then drawn oil. and the intcrln oil layer were filtered through a medium porosity fritted-glass crucible. The color and nature of the mat retained. indicate the tendency oithe oil to sludge after contact with water.

.11 rag and the 1 the crucible The lighter the mat the less the sludging tendency. These data were obtained on the oils prior to hunting the some for 20 hours at 200 7". y

b The appearance otthcse oils was noted after the Oil had been heated or 20hours at 200 F. and then permitted to stand at room temperature for an addition all 48 hours.

B Flccks" are somewhat larger than "spool-Is; mat indicates heavier residue than "cast"; "pink" with reference to residue indicates best and as appearance gets worse, colors deepen and darken, i e pink rcd purple brown, etc.

The additives of the present invention are effective to inhibit sediment and color formation and to disperse any sediment which might be present in the oil prior to introduction of the additive. In Table 1 are set forth data demonstrating many of these improvements. The furnace oil employed in these tests was a 60% virgin oil and catalytic cycle oil blend.

Whereas the crucible-appearance data set forth in Table 1 are an indication of the sludging tendency of the oil after contact with water, it will be noted that certain of the examples employing additives of the present invention give a relatively dark crucible appearance, yet the oils have a generally excellent appearance after aging. Thus, for example, the control run (Example 1) and that with phenylene diamine (Examples 16 and 17) indicate, in all tests, an oil very prone to sludging and whereas the crucible appearance in certain instances where the additives of the present invention were employed was somewhat dark, the appearance of the oil rafter aging belied any difiiculty. Oils inhibited with still other amines were not satisfactory when all of the tests were taken into consideration. Thus, for example, dibutylamine, lower molecular weight Duomeens and lower alkyl derivatives of ethylene diamine, diethylene triamine, etc. were tried and found wanting.

Set forth in Table 2 are data demonstrating the relative individual effectiveness of polyamines and salts thereof. Thus, it may be seen that the amine is somewhat more effective in its ability to insure a bright product, probably because of its having a primary amino nitrogen group which the carboxylic acid salts do not have. In this regard, it should be noted that when employing just one constituent nather than the combination, that an amount somewhat greater than 0.005% is preferred, e.g. about 0.01%. Nevertheless, the ability of either than amine or salts thereof to stabilize distillate fuels is apparent and the advantage of employing such materials in combination is clearly demonstrated by the data in Table 1. The

like is greatly facilitated by the use of concentrated oil solutions of such additives. It has, for example, been found especially desirable to use a 10% concentrate of such additive in an oil such as light catalytic cycle oil. A typical concentrate comprises solvent and 10% of an additive consisting of 80% of a suitable alkylene polyamine and 20% carboxylic acid salt of such an amine. Such concentrate is used for blending with the oil in whatever proportions may be desired and particularly to obtain a finished product containing the specified percentages of individual constituents. Whereas a 10% concentrate is specifically referred to, it should be understood that such concentration may vary widely and that those as high as 50% or more may be found useful under certain circumstances and are within the scope of the present invention. Moreover, although the light catalytic cycle oil is especially well adapted for use as the carrier or solvent in such a concentrate, any other suitable hydrocarbon oil may be employed.

As indicated above, the additives of the present invention are useful in straight run stocks (virgin) and blends of ditferent virgin stocks. Thus, as shown in Table 3, the improved color inhibition in such oils when employing an additive of the present invention is substantial.

I ltlcnrl of CuCl; su-ettrnml hint-Continent Virgin healer oil distillat and sulfuric acid tr t Tux Virgin heater oil distillate.

a Sulfuric acid treated t Texas heater oil distillate.

: Heated for one hour at F. and observed.

where R is an alkyl radical having from 16 to 20 carbon atoms, said small amount being sufficient to inhibit sludge deposition from said distillate fuel oil.

2. A fuel oil composition comprising a major proportion of a mixture of straight-run and catalytically cracked distillate fuel oils tending to deposit sludge and a small amount of a compound having the formula:

where R is the hydrocarbon radical derived from a fatty acid having from about 16 to about 20 carbon atoms, said small amount being sufiicient to inhibit sludge deposition from said mixture of oils.

3. A stable petroleum distillate fuel oil higher boiling than gasoline and boiling in the diesel, heating and furnace oi] range containing from about 0.001% to about 0.1 of an N-alkyl propylene diamine having from about 16 to about 20 carbon atoms and the general structure:

4. The fuel oil composition of claim 1 containing a small amount of a higher carboxylic acid salt of a compound having the formula:

where R is an alkyl radical having from 16 to 20 carbon atoms.

5. The stable petroleum distillate fuel oil of claim 1 in which the N-alkyl group is an alkyl radical containing 18 carbon atoms.

6. The stable petroleum distillate fuel of claim 1 in which the N-alkyl group is derived from tallow fatty acids.

7. The stable petroleum distillate fuel oil of claim 4 wherein the carboxylic acid salt is derived from olcic acid.

8. A stable petroleum distillate fuel oil higher boiling than gasoline comprising a substantial proportion of a cracked petroleum oil boiling chiefly in the range of from about 375 F. to about 750 F., from about 0.001% to about 0.1% of an N-alkyl propylene diamino compound having from about 16 to 20 carbon atoms in the N-alkyl group and the general structure: RNCH CH CH NH 9. The stable petroleum distillate fuel oil of claim 8 which contains from about 0.001% to about 0.1% of a higher carboxylic acid salt of said propylene diamine.

10. The fuel oil composition of claim 2 wherein the fatty acid is tallow fatty acid.

References Cited in the tile of this patent UNITED STATES PATENTS 2,305y674 Chenicek Dec. 22, 1942 2,329,251 Chenicek Sept. 14, 1943 2,369,490 Proell Feb. 13, 1945 2,684,292 Caron et al July 20, 1954 2,736,658 Pfohl et al. Feb. 28, 1956 2,771,348 Meguerian Nov. 20, 1956 

1. A FUEL OIL COMPOSITION COMPRISING A MAJOR PROPORTION OF A PETROLEUM DISTILLATE FUEL OIL HIGHER BOILING THAN GASOLINE AND A SMALL AMOUNT OF A COMPOUND HAVING THE FORMULA:
 4. THE FUEL OIL COMPOSITION OF CLAIM 1 CONTAINING A SMALL AMOUNT OF A HIGHER CARBOXYLIC ACID SALT OF A COMPOUND HAVING THE FORMULA: 